Agreed that a non running classic will drop value by 5-8k off the bat. Yes, engine may be original, but without first pulling it apart knowing what is wrong and even if could be rebuilt will sway everyone away with two exceptions...the right price OR someone who knows what to look for.

I agree that 15-18K as-is very accurate based on the color and options listed.

My opinion?

if the car is coveted and you are looking for a price to list, ANY guide is just that...a guide. IMO, you are looking, on what information provided here, shows $19k as low retail value.

"Low Retail Value
This vehicle would be in mechanically functional condition, needing only minor reconditioning. The exterior paint, trim and interior would show normal wear, needing only minor reconditioning. May also be a deteriorated restoration or a very poor amateur restoration. Most usable ‘as-is’. This value does not represent a ‘parts car’.
Note: Some of the vehicles in this publication could be considered ‘Daily Drivers’ and are not valued as a classic vehicle. When determining a value for a daily driver, it is recommended that the subscriber use the low retail value".

Since your Firebird is NOT running and engine is in unknown condition, in order to get to that $19k, one would assume that estimate is just that, an estimate.

There are enthusiasts that would buy the car as-is...but not at 19k. At least pull the motor and have engine inspected and certified by the shop as re-buildable. This would cost you time to remove and about $500 in shop labor. You will not take as bad a hit on price if you just said engine doesn't run.

IMO, I would take the hit and rebuild the engine for $3-4k and get it running well. It will cost you, sure...but at least you will be higher than the 19k valuation NADA places as a guide.

Or enlist the services of a certified appraiser for a value.

Any way you go absent getting the car running trying to get a value will sway such a guesstimate as much as 30-50%